Technical Field
The disclosure relates to a technical field of novel compounds relating to a structure and preparation method of a phosphorous-containing functionalized poly(arylene ether). The disclosure also relates to using the compound reacting with a compound having unsaturated double bonds to prepare a thermosetting composition which is friendly to environment and has excellent properties. The composition provides good fluidity and fast curing (i.e. cross-linking) rate. After curing, the composition presents excellent low dielectric constant and dielectric loss, high heat resistance and flame retardancy, and thus is suitable for prepregs, laminated sheets in printed circuits.
Description of Related Art
Currently, the electrical and electronic industry is rapidly developed. The developing direction of electronic devices is lightweight, high performance, high reliability, and environmental protection. The specific requirements of laminated sheets for printed circuits is expressed by high heat resistance, low thermal expansion coefficient, high resistance to heat and humid, environmentally friendly and flame retardancy, low dielectric constant and dielectric loss, and high elastic modulus. Therefore, the traditional epoxy resin has been unable to fully meet development needs of the printed circuit laminated sheets, and the applications of the poly(arylene ether) having high resistance, low dielectric constant and dielectric loss, as well as excellent toughness is more and more outstanding.
Traditional poly(arylene ether) resins are thermoplastic materials with a high molecular weight. The high viscous flow temperature, high melting viscosity, and poor solubility make the processability of the traditional poly(arylene ether) still not enough. In the application of laminated sheets for printed circuits, the high molecular-weight poly(arylene ether) is low-molecularly modified and used with a thermosetting resin. For example in patent CN101796132A, the poly(arylene ether) with a number average molecular weight below 5,000 and a cyanate are used in combination. The copper clad laminates made from this resin composition, relative to a pure is cyanate system, have a lower dielectric constant and dielectric loss, a better heat resistance, and a low water absorption rate. However, the active groups of the low molecular weight polyphenylene ether resin, in patent CN101796132A, has a small number and low activity, and almost does not participate the cross-linking reaction of cyanates. The cured product only can compose a semi-interpenetrating network (semi-IPN). The polyphenylene ether resin in the semi-IPN also cannot cross-link itself, and can only intersperse in the cross-linked network in a free state. Moreover, the compatibility of the poly(arylene ether) and other thermosetting resins is poor, and thus the resin phases are separated. The sheets made from the resin composition usually have defects of higher heat expansion coefficient and poorer heat stability, which are difficult to be solved.
For the low reactivity problem of polyphenylene, some further modified the low-molecular poly(arylene ether) with active groups, especially functional groups of unsaturated double bonds. For example, U.S. Pat. No. 5,071,922 of Nelissen, as well as U.S. Pat. Nos. 6,352,752 and 6,627,704 of Yager describes that may be widely applied in the thermosetting resin field. In CN102807658, the olefin resins containing butadiene with a greater molecular weight was used as a cross-linking agent, and used with components of functionalized polyphenylene ether resins and initiators to obtain a resin composition used in laminated sheets for printed circuits. The composition has very good dielectric properties and heat resistance, and is suitably used in high-frequency electronic circuit boards. However, the laminated sheets prepared for printed circuit boards have a problem of insufficient flame retardancy and a requirement of adding halogen flame retardants. However, the halogen flame retardants will produce dioxin, benzofuran, as well as irritant and corrosive gases when burning. Moreover, small molecular flame retardants often cause the decreased mechanical properties to deteriorate the material. Migration and volatile problems existing at the same time results in reduced performance and non-ideal flame retardant effect. Therefore, in the thermosetting resin composition, inventions of replacing the halogen flame retardants by organic phosphorous flame retardants emerge continuously, such as described in patents EP A 0384939, EP A 0384940, EP A 0408990, DE A 4308184 DE A 4308185, DE A 4308187, WO A 96/07685, and WO A 96/07686. In addition, for the laminated sheets in printed circuits, the current international standards require lead-free processes since the increasing environmental awareness. Therefore, the requirements for the process performance of the substrates are especially strict, especially the glass transition temperature (Tg) and the heat-resistance in a solder pot has become important issues that have to be overcome for persons skilled in the art.